Deamicis etal

1. 3D WEBGIS AND VISUALIZATION ISSUES FOR ARCHITECTURES AND LARGE
SITES
R. De Amicis., G. Conti, G. Girardi., M. Andreolli
Fondazione Graphitech, 38123 Trento, Italy –
(raffaele.de.amicis, giuseppe.conti, gabrio.girardi, michele.andreolli)@graphitech.it
Commission V, WG V/4
KEY WORDS: Geographical Information Systems (GIS), Spinning Globes, Cultural Heritage, Geodatabase, Interactive media
access
ABSTRACT:
Traditionally, within the field of archaeology and, more generally, within the cultural heritage domain, Geographical Information
Systems (GIS) have been mostly used as support to cataloguing activities, essentially operating as gateways to large geo-referenced
archives of specialised cultural heritage information. Additionally GIS have proved to be essential to help cultural heritage
institutions improve management of their historical information, providing the means for detection of otherwise hard-to-discover
spatial patterns, supporting with computation tools necessary to perform spatial clustering, proximity and orientation analysis.
This paper presents a platform developed to answer to both the aforementioned issues, by allowing geo-referenced cataloguing of
multi-media resources of cultural relevance as well as access, in a user-friendly manner, through an interactive 3D geobrowser which
operates as single point of access to the available digital repositories. The solution has been showcased in the context of “Festival
dell’Economia” (the Fair of Economics) a major event recently occurred in Trento, Italy and it has allowed visitors of the event to
interactively access an extremely large repository of information, as well as their metadata, available across the area of the
Autonomous Province of Trento, in Italy.
Within the event, an extremely large repository was made accessible, via the network, through web-services, from a 3D interactive
geobrowser developed by the authors. The 3D scene was enriched with a number of Points of Interest (POIs) linking to information
available within various databases. The software package was deployed with a complex hardware set-up composed of a large
composite panoramic screen covering a horizontal field of view of 240 degrees.
1. INTRODUCTION This paper describes the result of a work, commissioned by a
private contractor, which has provided the author with the
The fruition of Geographic Information (GI) from the Internet, chance to deploy an IT system that could emphasise this vision.
in a direct and interactive way, has enjoyed, in the last few The main challenge set by the contractor was to develop an
years, a significant growth. The unprecedented success of interactive solution that could be used to represents the various
mapping applications such as Microsoft Bing Maps or Google aspects of a territory, be these historical, economic,
Maps, is inevitably and radically changing the way people environmental, and to convey them in an innovative, trendy and
conceive the Internet and its content. These applications are in appealing way, that could be attractive for the largest possible
fact contributing to a radical paradigm shift in the way people audience, with the most diverse cultural background.
access the Internet, now increasingly based on geographical
locations rather than on their Internet address, promoting a Content-wise the solution had to emphasise the role of three
cultural change that could have unpredictable effects as already main factors: technological innovation, cultural identity and the
occurred in the case of other Web 2.0 disruptive technologies government of a territory.
such Facebook, which has recently overtaken emails in terms of
messages being exchanged. The final system had to be deployed within a major event,
namely the “Festival dell’Economia” (the Fair of Economics),
In the case of Geographic Information the possibility to play which takes place every year in Trento, Italy. The system had to
with an interactive mapping software in fact is changing the be used by the large audience to promote exploration,
user’s behaviour as they use platforms, such as Google Earth, communication and exchange of experience among the visiting
not only to find the shortest route to reach a given place but also public promoting the territory of the surrounding Province of
to identify touristic information within a particular area, or Trento, acting as a gateway to the adjoining areas and as a
simply for didactical or personal cultural growth, for instance to showcase to the cultural and economic heritage within the
explore areas of interest. In short these platforms allow the user Province.
to freely explore the territory.
For this reason it was essential for the system to be user friendly
2. INITIAL REQUIREMENTS OF THE PROJECT to help visitor enjoy their visit, motivating them to further
explore the surrounding areas after the visit to the site.
In fact the territory represents, almost directly, an instance of Furthermore the solution had to be robust, allowing visit of up
the cultural identity of a population, through its historical to several thousand people over few days, and had to ensure a
evolution, from an environmental, economic, societal or urban confortable experience also in the presence of groups of up to
planning point of view. 20 people.

2. When designing the solution the authors could benefit from To compensate for such a relatively low-resolution data, the
experience gained in the context of several research activities terrain was then textured, at very high scale (i.e. when flying out
and projects (Bertacchini et al. 2007; Conti et al., 2011; Conti et beyond the regional scale) with imagery from Landsat7
al., 2009; De Amicis et al. 2008). satellites (Landsat7, 2001), while at lower scales using imagery
acquired by the Province through airborne surveying, delivering
The first part of the work required gathering the digital assets ground resolution of 50 cm, covering an area of more than
that could be used to best represent the territory, its history and 6,000 square kilometres.
its heritage, namely the Digital Terrain Model (DTM) of the
Province of Trento, a complete orthophoto coverage of the This ensures an excellent graphical impact since the entire scene
Province, a very wide collection of historical photographs, maps become extremely rich in visual details. Additionally this
extracted from the historical cadastre, additional information represented the basis for the scene which could be interactively
regarding the most prominent and culturally relevant locations navigated with the use of a 3D geobrowser developed by the
in the area, but also locations of environmentally sustainable authors (Conti et al, 2009a; Simoes et al., 2009; Simoes et al.
businesses and, last but not least, a number of panoramic 2010). The user could then decide to see additional digital
pictures of the area. resources rendered over the terrain.
3. THE PROJECT CHALLENGE AND THE SOLUTION 4.2 Historical maps
DELIVERED
This datasets included not only information related to current
The challenge the authors had to face was to devise how to territory but also reference to historical asset. The most notable
represent all these apparently heterogeneous digital information example is show in Figure 1, which illustrates the historical
in an interactive manner yet delivering and harmonious maps of forty city councils across the Trentino Province, which
experience that could represent the territory in an engaging and could be rendered on top of the terrain in 3D over an area of
user friendly way. more than 3,200 square kilometres.
The solution identified made use of a software infrastructure
based on a 3D geobrowser developed by the authors (see section
5 - software infrastructure) and an advanced panoramic display
system set-up to cover –at high resolution- an horizontal field of
240 degree (see section 6 - hardware set-up).
All the data repositories ware not stored any more in a standard
way, within databases or file systems, but they were geo-
referenced. Participants could enter the site and interrogate the
system: any of the visitor user fly around the scene in an
interactive manner and accessing the multimedia content. One
may argue that the system could be accessed by one user at time
only, but in fact the set-up allowed true group-wise experience
whereby a small community of users access the territory,
discover information of interest, read documents of relevance
and exchange positions and points of view, comment in a
collaborative manner.
The large volume covered by the visualisation set-up ensured
that the experience become participatory in the very similar
manner to a traditional visit to a given site with a group of
persons. However this approach has allowed moving beyond the
issue of ensuring collaborative access to digital assets through
different set-ups sharing the same virtual environment accessed
through a number of remote sessions.
4. ASSET AVAILABLE AND ITS PROCESSING
4.1 The 3D model of the terrain Figure 1: the system in use while showing the historical maps
The 3D scene of the region was built with the use of a Digital It must be noted that this required an extensive preparation work
Terrain Model (DTM) based on the Shuttle Radar Topography as the historical cadastral maps, dating back to the end of
Mission (SRTM) dataset made publicly available by NASA. nineteen century, had been initially made available as paper
based maps. The various map sheets were classified according
Although the dataset provides only 90 meter ground resolution to geographical grid of approximately 2 by 2 kilometres. The
this was regarded as more than adequate given the scope of the initial set of paper documents, which had been previously
application. In fact the adoption of a higher resolution DEM, scanned by the local cultural heritage department, was made
such as the one available by Provincia di Trento which has an available to the authors as high resolution set of approximately
average ground resolution of 2 meters, would have added a 2,000 digital images.
significantly higher strain in terms of required graphical
computing power due to the very high resolution of the screen However their use within the geo-referenced 3D globe, used for
used (see section 6 - hardware set-up). this project, required the application of an affine transformation

3. to yield ortho-rectified images to be rendered within the 3D
scene.
Once ortho-rectified the various independent sets of map sheets
had to be grouped and stitched together in order to achieve a
single, seamless coverage of a given city council. This process
had to be repeated for each set of map sheet which fell within
the same administrative borders.
This yielded a set of different maps, one for each administrative
area, which had to be merged into a single seamless data
structure.
However to do so a further step was required to remove, from
each set of map sheets corresponding to an administrative
border, the empty areas around the borders and to make this
areas transparent to allow proper fitting with other adjoining
maps.
Once all images had been blended into a single coverage set this
was pre-processed and structured into squared images sets
whose side measured 0.04 degree. Each image constituted the
top of a pyramid of images of 512x512 pixels at five different
levels of detail, created by subdividing the parent image into a
set of 4x4 images. The final result was a set of fifty thousand
images structured within file system according to their level of
resolution and position.
Figure 2: a screenshot showing the location of cultural
4.3 Other information on locations of relevance
relevance
Such a wide data repository was complemented by information
available within a database of the Culture Department of the
local Province of Trento. This contained information on points
of interest of cultural relevance including, but not limited to,
museums, places of worship (e.g. churches, monasteries,
cemeteries etc.), location of areas of historical military
relevance including old fortresses, trenches, and areas subject to
bombing during the Second World War.
A further dataset contained information collected by a local
trust focusing on initiatives to improve sustainability and reduce
carbon footprint. The database contained, among other,
information on local farms capable to promote local produce
(therefore reducing emission of carbon dioxide), industries
deploying green policies, renewable energy sources etc. Figure 3: a screenshot showing the various cultural resources
These repositories were finally complemented by a large set of available in the area
360 high-resolution panoramas distributed over the territory of
the Province shot at location of high touristic impact such as
mountain peaks etc. 5. SOFTWARE INFRASTRUCTURE
This extremely large repository was made accessible, via the The software developed for the purpose of the fair, as presented
network through web-services, from a 3D interactive in this paper, was based on top of the platform, developed by
geobrowser developed by the authors. The technical details of the authors (Conti et al, 2009a; Simoes et al., 2009; Simoes et
the software infrastructure are detailed in the following section. al. 2010), for interactive web-based fruition and management of
The information available through the aforementioned geographical information.
repositories were integrated and made available, within the 3D
scene, as a number of Points of Interest (POIs) linking to The framework is composed, on the one hand, of a complex
information available within the different databases. federation of server-side component and, on the other, it
features a web-based 3D client.
Whenever the user wanted to retrieve additional information on
a given point of interest, they could click on each of these POIs. The client is fully developed as pure Java™ application
As result a panel would be automatically formatted with all the ensuring portability to all the most popular Operating Systems
multimedia content available, which could include textual (OS) including Windows, Macintosh and Linux platforms. The
description and images, videos to name but a few, all client can be deployed as standalone software or, more
automatically formatted from the information available within conveniently, as applet or Java Web Start™ application.
the database.

4. 5.1 Resource management resolution as previously discussed when detailing the
production of historical maps.
The 3D scene represents the base on top of which all the other
detests are rendered. The system, during handshake, downloads This repository, which is static in nature, allows fast delivery on
the list of resources to be made available to the user. As soon as information at the server side without use of a database through
the client is started the client connects to the servers and an efficient mechanism of storing, compression and indexing of
downloads the configuration corresponding to the given profile. the various patches of images at different resolution. The clients
This includes both the tools available within the interface and sends to the server a standardised request (e.g. as WMS request)
the datasets that the client will be granted access to. After for a given portion of terrain. The servlet receives the request
successful authentication tools and resources are grouped within and fetches the corresponding repository directly at the file
two panels, rendered on top of the main window, sliding on the system level, encoding the response as WMS messages via
side of the screen once not needed. HTTP. As a result the server does not need to invoke the full
service stack involving use of Geoserver, other libraries as well
During handshake the client requests from thee server the list of as the database. This very simple, yet streamlined approach
resources assigned to a given profile. A servlet responds with an ensures extremely high performances when dealing with static
XML which details both the information to be shown to the information, often with an order of magnitude improvement in
user, which will be used as label of a table of content. The latter terms of response time.
is shown at the right most side of the screen within a sliding
panel and can be used to conveniently access the various This approach is extremely beneficial as it allows accessing,
resources. This information is used by the client to create a set within a context such as a solution developed for cultural
of layers, these are logical sets of resourced packed together, applications, to information made available by public
that can be visualised in various ways. These can be layers administrations for operational activities (e.g. for planning or
containing maps, images, but also multimedia data etc. other technical and administrative reasons) in an interoperable
manner. This way digital resources such as orthophoto imagery,
Layers can also be used to create logically stacked sets of cadastral maps, geographical data on planning, to name but a
graphical information over the terrain. In other words their order few, can be accessed in a completely interoperable manner, thus
is used by the system to determine the visibility of one dataset maximising the scope of the resources available.
with respect to the others, as if they were different layers of
graphical resources draped over the terrain in a given order. The federated approach moves a step further in that if some
adaptation is required, for instance to perform re-projection of
The XML detailing the configuration additionally specifies the existing resources to the reference system in use by the client, or
internet location where each resource is located. In fact the to perform a transformation of data model, this can be
entire infrastructure is based upon the paradigm of the so-called performed on the fly by a dedicated web service.
Spatial Data Infrastructure (SDI) a set of federated web services
providing access to georeferenced information via standard Structured information is typically stored within a database with
communication protocols. spatial extension (geodatabase). This way additional multimedia
or alphanumeric resources can also be accessed directly from
When the user selects a resource from the Table of Content the the client. This is the case of repositories containing cultural
client redirects the request to the web-service providing access information as detailed in the previous sections.
to the relevant dataset.
6. HARDWARE SET-UP
The various web services are deployed within a Java Enterprise
Edition framework. Whenever possible the business intelligence Due to the large number of expected visitors, the visualisation
required at the server level is ensure through an EJB (Enterprise setup had to ensure concurrent vision by group of up to 20
Java Bean) coupled to a Servlet which is responsible for the people. For this reason, after a comprehensive study of various
communication with the client. Most notably the solutions, the authors opted for a very effective visualisation
communication –whenever possible- is performed with the use solution based on a curved screen covering 240° field of view.
of standards from Open Geospatial Consortium (OGC, 2011).
In particular this ensures that imagery (e.g. maps) or vector A self-standing structure was used to create a cylindrical
information (e.g. roads) can be transmitted in a standardised projection surface where four Epson EB-G5200 projectors
manner through protocols such as Web Map Service (WMS) or delivered a composite image of 4096x768 pixels at 5000 lm
Web Feature Service (WFS). across the 240° curved screen with a radius of 2.2 meters. The
projectors were mounted on the upper structure of the projection
From the server side this is delivered through a set of software screen ensuring a large shadow-free area within the cylindrical
components developed on top of Geoserver (Geoserver, 2011) space.
and GeoTools (GeoTools, 2011), a lower level toolkit which
can be used to implement geographical applications. The large panoramic screen was powered by a PC workstation,
configured with two nVidia GTX480 video cards, with a total of
These server components in turn rely on one or more data 3 GB dedicated video memory. The PC was used to run both the
repositories which can be available locally or yet within other client and the server components including JBoss, Apache etc.
server within the federation. Local data, typically available
through file systems, include satellite or airborne imagery. The two video outputs from the nVidia video cards were
These resources are not stored within a database but within a connected to a Viosio Black Box used to create a single virtual
structured file system. A set of structured folders allows storing high-resolution screen which is then split into four regions, each
imagery according to a standardised subdivision in “tiles”, i.e. corresponding to one of the sectors of the screen. The Black
patches of terrain at increasingly smaller scale and higher Box was configured to ensure proper edge blending and

5. correction of the distortion across the four projectors in order to The solution had to be respond to a number of strict constraints
deliver a single seamless image. including the possibility to be experienced by several users at
time, being robust, provide access to heterogeneous
information, be engaging, and capable to attract the largest
possible audience. The solution has been detailed from the
software and hardware standpoint.
Currently the authors are also extending the solution presented
in this paper with a multi-touch system capable to manage 32
simultaneous points of contact. This solution is being used to
create a collaborative environment where several users at the
same time not only visualise information over a screen but also
interact with its content in a very user friendly way composing
information of relevance over a large screen. This will bring to
new scenarios of explorative collaboration.
Figure 4: a picture of the tessellated display deployed
7. THE SYSTEM IN USE
The entire set-up was deployed for an entire week within a large
tent, open to visitors, within one of the main square of the city.
As result the set-up was experienced by thousands of people
during the week-long fair of economics.
Although no formal assessment could be made, given the
context of the set-up, the public showed great interest for the
solution that was often regarded as very informative and
pleasant. Several users reported explicitly that the set-up had Figure 6: the multi-touch panel being used as further extension
fuelled their interest towards the surrounding area, and had of the system.
acted as excellent promotional platform. Most interestingly
several local visitors, i.e. those living in the city, regarded the 9. REFERENCES AND/OR SELECTED
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